2019-11-30
2131
#css
Craig Buckler
10539
Nov 30, 2019 â‹… 7 min read

Jank-free page loading with media aspect ratios

Craig Buckler Freelance UK IT consultant specializing in HTML5 webby stuff.

Recent posts:

A Guide To Wrapper Vs. Container Classes In CSS

A guide to wrapper vs. container classes in CSS

A breakdown of the wrapper and container CSS classes, how they’re used in real-world code, and when it makes sense to use one over the other.

Temitope Oyedele
Jul 7, 2025 â‹… 10 min read
Stagehand and Gemini logos on a gradient background symbolizing AI web automation

How to build a web-based AI agent with Stagehand and Gemini

This guide walks you through creating a web UI for an AI agent that browses, clicks, and extracts info from websites powered by Stagehand and Gemini.

Elijah Asaolu
Jul 4, 2025 â‹… 8 min read
Getting Started With Claude 4 API: A Developer's Walkthrough

Getting started with Claude 4 API: A developer’s walkthrough

This guide explores how to use Anthropic’s Claude 4 models, including Opus 4 and Sonnet 4, to build AI-powered applications.

Andrew Baisden
Jul 3, 2025 â‹… 16 min read
ai dev tool power rankings

AI dev tool power rankings & comparison [July 2025 edition]

Which AI frontend dev tool reigns supreme in July 2025? Check out our power rankings and use our interactive comparison tool to find out.

Chizaram Ken
Jul 2, 2025 â‹… 3 min read
View all posts

3 Replies to "Jank-free page loading with media aspect ratios"

  1. This is great but I am struggling here a bit. For example. On my photo hosting site, I display a random selection of images. These are shown as thumbnails. See here:

    https://www.ag2si.com/gallerysoft/

    What I am having difficulty with understanding is the following:
    I created the site as responsive, so when you grow or shrink the browser, the thumbnails grow and shrink as well.
    I know the aspect ratio of the original image.
    I use flex and specify something like so
    flex:${aspect};
    However, since the page is dynamic in size, I do not know what size the thumbnails will be. Therefore, I cannot add the width and height attributes to the src tag. And a pagespeed web dev site recommends I should include them.

    Does that make sense?

    Thanks
    JT

  2. You set the width and height of the original image – not the dimensions it’ll be displayed at.

    So a 600×450 image has width=”600″ height=”450″ regardless of how it appears on the page. The browser will calculate it’s aspect ratio so, if the resulting image width is 300px, it’ll reserve 225px of vertical space before the image has started to load.

    Therefore, width=”4″ height=”3″ and width=”8000″ height=”6000″ would act identically – they’re all the same aspect ratio.

Leave a Reply